This is a bit esoteric, but at the time of this writing, I am interested in encodings that contain at least one letter and and least one number. For a given length encoding, the Crockford scheme offers a bigger set of strings that meet this requirement than RFC 4648.

There is a similarly named CPAN module called Encode::Base32::Crockford. It uses the Crockford encoding scheme but it only works on numbers (as of the time this module was written).

Base32 and Base64 are almost always employed to encode binary strings into a human readable form. Encode::Base32::Crockford::base32_encode dies when you try to encode a string that is not string of ASCII digits.